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Diffstat (limited to 'lib/diameter/src/base/diameter_capx.erl')
-rw-r--r-- | lib/diameter/src/base/diameter_capx.erl | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/lib/diameter/src/base/diameter_capx.erl b/lib/diameter/src/base/diameter_capx.erl new file mode 100644 index 0000000000..6c4d60ee9b --- /dev/null +++ b/lib/diameter/src/base/diameter_capx.erl @@ -0,0 +1,391 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2010-2011. All Rights Reserved. +%% +%% The contents of this file are subject to the Erlang Public License, +%% Version 1.1, (the "License"); you may not use this file except in +%% compliance with the License. You should have received a copy of the +%% Erlang Public License along with this software. If not, it can be +%% retrieved online at http://www.erlang.org/. +%% +%% Software distributed under the License is distributed on an "AS IS" +%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See +%% the License for the specific language governing rights and limitations +%% under the License. +%% +%% %CopyrightEnd% +%% + +%% +%% This module builds CER and CEA records for use during capabilities +%% exchange. All of a CER/CEA is built from AVP values configured on +%% the service in question but values for Supported-Vendor-Id, +%% Vendor-Specific-Application-Id, Auth-Application-Id and +%% Acct-Application-id are also obtained using an older method that +%% remains only for backwards compatibility. With this method, each +%% dictionary module was required to export a cer/0 that returned a +%% diameter_base_CER record (or corresponding list, although the list +%% is also a later addition). Each returned CER contributes its member +%% values for the aforementioned four AVPs to the resulting CER, with +%% remaining AVP's either unspecified or identical to those configured +%% on the service. Auth-Application-Id and Acct-Application-id were +%% originally treated a little differently, each callback being +%% required to return either no value of the same value as the other +%% callbacks, but this coupled the callback modules unnecessarily. (A +%% union is backwards compatible to boot.) +%% +%% Values obtained from the service and callbacks are all included +%% when building a CER. Older code with only callback can continue to +%% use them, newer code should probably stick to service configuration +%% (since this is more explicit) or mix at their own peril. +%% +%% The cer/0 callback is now undocumented (despite never being fully +%% documented to begin with) and should be considered deprecated even +%% by those poor souls still using it. +%% + +-module(diameter_capx). + +-export([build_CER/1, + recv_CER/2, + recv_CEA/2, + make_caps/2]). + +-include_lib("diameter/include/diameter.hrl"). +-include("diameter_internal.hrl"). +-include("diameter_gen_base_rfc3588.hrl"). + +-define(SUCCESS, 2001). %% DIAMETER_SUCCESS +-define(NOAPP, 5010). %% DIAMETER_NO_COMMON_APPLICATION +-define(NOSECURITY, 5017). %% DIAMETER_NO_COMMON_SECURITY + +-define(NO_INBAND_SECURITY, 0). +-define(TLS, 1). + +%% =========================================================================== + +-type tried(T) :: {ok, T} | {error, {term(), list()}}. + +-spec build_CER(#diameter_caps{}) + -> tried(#diameter_base_CER{}). + +build_CER(Caps) -> + try_it([fun bCER/1, Caps]). + +-spec recv_CER(#diameter_base_CER{}, #diameter_service{}) + -> tried({[diameter:'Unsigned32'()], + #diameter_caps{}, + #diameter_base_CEA{}}). + +recv_CER(CER, Svc) -> + try_it([fun rCER/2, CER, Svc]). + +-spec recv_CEA(#diameter_base_CEA{}, #diameter_service{}) + -> tried({[diameter:'Unsigned32'()], + [diameter:'Unsigned32'()], + #diameter_caps{}}). + +recv_CEA(CEA, Svc) -> + try_it([fun rCEA/2, CEA, Svc]). + +make_caps(Caps, Opts) -> + try_it([fun mk_caps/2, Caps, Opts]). + +%% =========================================================================== +%% =========================================================================== + +try_it([Fun | Args]) -> + try apply(Fun, Args) of + T -> {ok, T} + catch + throw: ?FAILURE(Reason) -> {error, Reason} + end. + +%% mk_caps/2 + +mk_caps(Caps0, Opts) -> + {Caps, _} = lists:foldl(fun set_cap/2, + {Caps0, #diameter_caps{_ = false}}, + Opts), + Caps. + +-define(SC(K,F), + set_cap({K, Val}, {Caps, #diameter_caps{F = false} = C}) -> + {Caps#diameter_caps{F = cap(K, Val)}, C#diameter_caps{F = true}}). + +?SC('Origin-Host', origin_host); +?SC('Origin-Realm', origin_realm); +?SC('Host-IP-Address', host_ip_address); +?SC('Vendor-Id', vendor_id); +?SC('Product-Name', product_name); +?SC('Origin-State-Id', origin_state_id); +?SC('Supported-Vendor-Id', supported_vendor_id); +?SC('Auth-Application-Id', auth_application_id); +?SC('Inband-Security-Id', inband_security_id); +?SC('Acct-Application-Id', acct_application_id); +?SC('Vendor-Specific-Application-Id', vendor_specific_application_id); +?SC('Firmware-Revision', firmware_revision); + +set_cap({Key, _}, _) -> + ?THROW({duplicate, Key}). + +cap(K, V) + when K == 'Origin-Host'; + K == 'Origin-Realm'; + K == 'Vendor-Id'; + K == 'Product-Name' -> + V; + +cap('Host-IP-Address', Vs) + when is_list(Vs) -> + lists:map(fun ipaddr/1, Vs); + +cap('Firmware-Revision', V) -> + [V]; + +cap(_, Vs) + when is_list(Vs) -> + Vs; + +cap(K, V) -> + ?THROW({invalid, K, V}). + +ipaddr(A) -> + try + diameter_lib:ipaddr(A) + catch + error: {invalid_address, _} = T -> + ?THROW(T) + end. + +%% bCER/1 +%% +%% Build a CER record to send to a remote peer. + +%% Use the fact that diameter_caps has the same field names as CER. +bCER(#diameter_caps{} = Rec) -> + #diameter_base_CER{} + = list_to_tuple([diameter_base_CER | tl(tuple_to_list(Rec))]). + +%% rCER/2 +%% +%% Build a CEA record to send to a remote peer in response to an +%% incoming CER. RFC 3588 gives no guidance on what should be sent +%% here: should we advertise applications that the peer hasn't sent in +%% its CER (aside from the relay application) or not? If we send +%% applications that the peer hasn't advertised then the peer may have +%% to be aware of the possibility. If we don't then we just look like +%% a server that supports a subset (possibly) of what the client +%% advertised, so this feels like the path of least incompatibility. +%% However, the current draft standard (draft-ietf-dime-rfc3588bis-26, +%% expires 24 July 2011) says this in section 5.3, Capabilities +%% Exchange: +%% +%% The receiver of the Capabilities-Exchange-Request (CER) MUST +%% determine common applications by computing the intersection of its +%% own set of supported Application Id against all of the application +%% identifier AVPs (Auth-Application-Id, Acct-Application-Id and Vendor- +%% Specific-Application-Id) present in the CER. The value of the +%% Vendor-Id AVP in the Vendor-Specific-Application-Id MUST NOT be used +%% during computation. The sender of the Capabilities-Exchange-Answer +%% (CEA) SHOULD include all of its supported applications as a hint to +%% the receiver regarding all of its application capabilities. +%% +%% Both RFC and the draft also say this: +%% +%% The receiver only issues commands to its peers that have advertised +%% support for the Diameter application that defines the command. A +%% Diameter node MUST cache the supported applications in order to +%% ensure that unrecognized commands and/or AVPs are not unnecessarily +%% sent to a peer. +%% +%% That is, each side sends all of its capabilities and is responsible for +%% not sending commands that the peer doesn't support. + +%% 6.10. Inband-Security-Id AVP +%% +%% NO_INBAND_SECURITY 0 +%% This peer does not support TLS. This is the default value, if the +%% AVP is omitted. +%% +%% TLS 1 +%% This node supports TLS security, as defined by [TLS]. + +rCER(CER, #diameter_service{capabilities = LCaps} = Svc) -> + #diameter_base_CEA{} + = CEA + = cea_from_cer(bCER(LCaps)), + + RCaps = capx_to_caps(CER), + SApps = common_applications(LCaps, RCaps, Svc), + + {SApps, + RCaps, + build_CEA(SApps, + LCaps, + RCaps, + CEA#diameter_base_CEA{'Result-Code' = ?SUCCESS})}. + +build_CEA([], _, _, CEA) -> + CEA#diameter_base_CEA{'Result-Code' = ?NOAPP}; + +build_CEA(_, LCaps, RCaps, CEA) -> + case common_security(LCaps, RCaps) of + [] -> + CEA#diameter_base_CEA{'Result-Code' = ?NOSECURITY}; + [_] = IS -> + CEA#diameter_base_CEA{'Inband-Security-Id' = IS} + end. + +%% common_security/2 + +common_security(#diameter_caps{inband_security_id = LS}, + #diameter_caps{inband_security_id = RS}) -> + cs(LS, RS). + +%% Unspecified is equivalent to NO_INBAND_SECURITY. +cs([], RS) -> + cs([?NO_INBAND_SECURITY], RS); +cs(LS, []) -> + cs(LS, [?NO_INBAND_SECURITY]); + +%% Agree on TLS if both parties support it. When sending CEA, this is +%% to ensure the peer is clear that we will be expecting a TLS +%% handshake since there is no ssl:maybe_accept that would allow the +%% peer to choose between TLS or not upon reception of our CEA. When +%% receiving CEA it deals with a server that isn't explicit about its choice. +%% TODO: Make the choice configurable. +cs(LS, RS) -> + Is = ordsets:to_list(ordsets:intersection(ordsets:from_list(LS), + ordsets:from_list(RS))), + case lists:member(?TLS, Is) of + true -> + [?TLS]; + false when [] == Is -> + Is; + false -> + [hd(Is)] %% probably NO_INBAND_SECURITY + end. +%% The only two values defined by RFC 3588 are NO_INBAND_SECURITY and +%% TLS but don't enforce this. In theory this allows some other +%% security mechanism we don't have to know about, although in +%% practice something there may be a need for more synchronization +%% than notification by way of an event subscription offers. + +%% cea_from_cer/1 + +%% CER is a subset of CEA, the latter adding Result-Code and a few +%% more AVP's. +cea_from_cer(#diameter_base_CER{} = CER) -> + lists:foldl(fun(F,A) -> to_cea(CER, F, A) end, + #diameter_base_CEA{}, + record_info(fields, diameter_base_CER)). + +to_cea(CER, Field, CEA) -> + try ?BASE:'#get-'(Field, CER) of + V -> ?BASE:'#set-'({Field, V}, CEA) + catch + error: _ -> CEA + end. + +%% rCEA/2 + +rCEA(CEA, #diameter_service{capabilities = LCaps} = Svc) -> + RCaps = capx_to_caps(CEA), + SApps = common_applications(LCaps, RCaps, Svc), + IS = common_security(LCaps, RCaps), + + {SApps, IS, RCaps}. + +%% capx_to_caps/1 + +capx_to_caps(#diameter_base_CEA{'Origin-Host' = OH, + 'Origin-Realm' = OR, + 'Host-IP-Address' = IP, + 'Vendor-Id' = VId, + 'Product-Name' = PN, + 'Origin-State-Id' = OSI, + 'Supported-Vendor-Id' = SV, + 'Auth-Application-Id' = Auth, + 'Inband-Security-Id' = IS, + 'Acct-Application-Id' = Acct, + 'Vendor-Specific-Application-Id' = VSA, + 'Firmware-Revision' = FR, + 'AVP' = X}) -> + #diameter_caps{origin_host = OH, + origin_realm = OR, + vendor_id = VId, + product_name = PN, + origin_state_id = OSI, + host_ip_address = IP, + supported_vendor_id = SV, + auth_application_id = Auth, + inband_security_id = IS, + acct_application_id = Acct, + vendor_specific_application_id = VSA, + firmware_revision = FR, + avp = X}; + +capx_to_caps(#diameter_base_CER{} = CER) -> + capx_to_caps(cea_from_cer(CER)). + +%% --------------------------------------------------------------------------- +%% --------------------------------------------------------------------------- + +%% common_applications/3 +%% +%% Identify the (local) applications to be supported on the connection +%% in question. + +common_applications(LCaps, RCaps, #diameter_service{applications = Apps}) -> + LA = app_union(LCaps), + RA = app_union(RCaps), + + lists:foldl(fun(I,A) -> ca(I, Apps, RA, A) end, [], LA). + +ca(Id, Apps, RA, Acc) -> + Relay = lists:member(?APP_ID_RELAY, RA), + #diameter_app{alias = Alias} = find_app(Id, Apps), + tcons(Relay %% peer is a relay + orelse ?APP_ID_RELAY == Id %% we're a relay + orelse lists:member(Id, RA), %% app is supported by the peer + Id, + Alias, + Acc). +%% 5.3 of the RFC states that a peer advertising itself as a relay must +%% be interpreted as having common applications. + +%% Extract the list of all application identifiers from Auth-Application-Id, +%% Acct-Application-Id and Vendor-Specific-Application-Id. +app_union(#diameter_caps{auth_application_id = U, + acct_application_id = C, + vendor_specific_application_id = V}) -> + set_list(U ++ C ++ lists:flatmap(fun vsa_apps/1, V)). + +vsa_apps(#'diameter_base_Vendor-Specific-Application-Id' + {'Auth-Application-Id' = U, + 'Acct-Application-Id' = C}) -> + U ++ C; +vsa_apps(L) -> + Rec = ?BASE:'#new-'('diameter_base_Vendor-Specific-Application-Id', L), + vsa_apps(Rec). + +%% It's a configuration error for a locally advertised application not +%% to be represented in Apps. Don't just match on lists:keyfind/3 in +%% order to generate a more helpful error. +find_app(Id, Apps) -> + case lists:keyfind(Id, #diameter_app.id, Apps) of + #diameter_app{} = A -> + A; + false -> + ?THROW({app_not_configured, Id}) + end. + +set_list(L) -> + sets:to_list(sets:from_list(L)). + +tcons(true, K, V, Acc) -> + [{K,V} | Acc]; +tcons(false, _, _, Acc) -> + Acc. |